[Show abstract][Hide abstract] ABSTRACT: Background:
Brugada syndrome (BrS)-type electrocardiogram (ECG) is concealed by complete right bundle-branch block (CRBBB) in some cases of BrS. Clinical significance of BrS masked by CRBBB is not well known.Methods and Results:We reviewed an ECG database of 326 BrS patients who had type 1 ECG with or without pilsicainide. "BrS masked by CRBBB" was defined on ECG as <2-mm elevation of the J point at the time of CRBBB in the right precordial leads, and BrS-type J-point elevation ≥2 mm at the time of normalized QRS complex on relieved CRBBB. We identified 25 BrS patients (7.7%) with persistent (n=12) or intermittent CRBBB (n=13). Relief of CRBBB by pacing was performed in patients with persistent CRBBB. The prevalence of BrS masked by CRBBB was 3.1% (10/326 patients). Three patients had type 1 ECG, and 7 patients had type 2 or 3 ECG on relief of CRBBB. Two of these 10 patients had lethal arrhythmic events during the follow-up period (mean, 86.4±57.2 months). There was no prognostic difference between BrS masked by CRBBB and other BrS.
In a small BrS population, CRBBB can completely mask typical BrS-type ECG. BrS masked by CRBBB is associated with the same risk of fatal ventricular tachyarrhythmia as other BrS.
Full-text · Article · Oct 2015 · Circulation Journal
[Show abstract][Hide abstract] ABSTRACT: This book highlights recent advances in beta blockers research. Beta blockers have been used for the treatment of several clinical conditions and it is of paramount importance to understand their role and applications. Chapters of the book were written by experts in the fields of vascular disease, plastic surgery, cardiovascular medicine, pharmaceutical medicine and physiology from various countries such as the United States, the United Kingdom, Brazil, Japan and New Zealand.
Clinical topics on recent advances in â-blockers research covered in this book include the clinical effectiveness of â-blockers in patients with peripheral arterial disease, abdominal aortic aneurysm, heart failure, acute coronary syndrome, pulmonary hypertension, object memory recognition, portal hypertension and infantile hemangioma. These chapters were written by authors who are experts in their fields and by researchers who are most up-to-date in the recent literature on advances in â-blockers research.
This book would be of great value for researchers in the field of â-blockers and adds up-to-date knowledge on the use of this class of drugs in several diseases. It will certainly contribute additional, valuable knowledge to what is already known about this very important class of drugs. This book is also a valuable source of information for residents and medical students to help enable them to keep abreast with recent evidence concerning beta blockers.
[Show abstract][Hide abstract] ABSTRACT: Ambulatory measurement of intrathoracic impedance (ITI) with an implanted device may detect increases in pulmonary fluid retention early, but the clinical utility of this method is not well established. The goal of this study was to test whether conventional ITI-derived parameters can diagnose fluid retention that may cause early stage heart failure (HF).Methods and Results:HF patients implanted with high-energy devices with OptiVol (Medtronic) monitoring were enrolled in this study. Patients were monitored remotely. At both baseline and OptiVol alert, patients were assessed on standard examinations, including analysis of serum brain natriuretic peptide (BNP). From April 2010 to August 2011, 195 patients from 12 institutes were enrolled. There were 154 primary OptiVol alert events. BNP level at the alerts was not significantly different from that at baseline. Given that ITI was inversely correlated with log BNP, we added a criterion specifying that the OptiVol alert is triggered only when ITI decreases by ≥4% from baseline. This change improved the diagnostic potential of increase in BNP at OptiVol alert (sensitivity, 75%; specificity, 88%).
BNP increase could not be identified based on OptiVol alert. Decrease in ITI ≥4% compared with baseline, in addition to the alert, however, may be a useful marker for the likelihood of HF (Clinical trial info: UMIN000003351).
Preview · Article · Mar 2015 · Circulation Journal
[Show abstract][Hide abstract] ABSTRACT: Background:
Risk stratification in patients with Brugada syndrome for primary prevention of sudden cardiac death is still an unsettled issue. A recent consensus statement suggested the indication of implantable cardioverter defibrillator (ICD) depending on the clinical risk factors present (spontaneous type 1 Brugada electrocardiogram (ECG) [Sp1], history of syncope [syncope], and ventricular fibrillation during programmed electrical stimulation [PES+]). The indication of ICD for the majority of patients, however, remains unclear.
Methods and results:
A total of 218 consecutive patients (211 male; aged 46 ± 13 years) with a type 1 Brugada ECG without a history of cardiac arrest who underwent evaluation for ICD including electrophysiological testing were examined retrospectively. During a mean follow-up period of 78 months, 26 patients (12%) developed arrhythmic events. On Kaplan-Meier analysis patients with each of Sp1, syncope, or PES+ suffered arrhythmic events more frequently (P=0.018, P<0.001, and P=0.003, respectively). On multivariate analysis Sp1 and syncope were independent predictors of arrhythmic events. When dividing patients according to the number of these 3 risk factors present, patients with 2 or 3 risk factors experienced arrhythmic events more frequently than those with 0 or 1 risk factor (23/93 vs. 3/125; P<0.001).
Syncope, Sp1, and PES+ are important risk factors and the combination of these risks well stratify the risk of later arrhythmic events.
Full-text · Article · Nov 2014 · Circulation Journal
[Show abstract][Hide abstract] ABSTRACT: Objectives
This study aimed to determine the usefulness of the combination of several electrocardiographic (ECG) markers on risk assessment of ventricular fibrillation (VF) in patients with Brugada syndrome (BrS).
Detection of high/low-risk BrS patients using a noninvasive method is an important issue in the clinical setting. Several ECG markers related to depolarization and repolarization abnormalities have been reported, but the relationship and usefulness of these parameters in VF events are unclear.
Baseline characteristics of 246 consecutive patients (236 males; mean age, 47.6±13.6 years) with Brugada type ECG, including 13 patients with a history of VF and 40 patients with a history of syncopal episodes, were retrospectively analyzed. During the mean follow-up period of 45.1 months, VF in 23 patients and sudden cardiac death (SCD) in one patient were observed. Clinical/genetic and electrocardiographic parameters were compared with VF/SCD events.
By univariate analysis, history of VF, history of syncopal episodes, paroxysmal atrial fibrillation , spontaneous type 1 pattern in the precordial leads, ECG markers of depolarization abnormalities (PQ >200 ms, QRS duration ≥120 ms, and fragmented QRS [f-QRS]), and those of repolarization abnormalities (infero-lateral early repolarization [ER] pattern and QT prolongation) were associated with later cardiac events. By multivariable analysis, history of VF, history of syncopal episodes, infero-lateral ER pattern, f-QRS were independent predictors of documented VF and SCD (odds ratio, 19.61, 28.57, 2.87, and 5.21, respectively, P<0.05). Kaplan-Meier curves showed that the presence/absence of infero-lateral ER and f-QRS provided a worse/better prognosis (log-rank test, P<0.01).
The combination of depolarization and repolarization abnormalities in BrS is associated with later VF events. The combination of these abnormalities is useful for detecting high- and low-risk BrS patients.
Full-text · Article · May 2014 · Journal of the American College of Cardiology
[Show abstract][Hide abstract] ABSTRACT: Patients with cardiac implantable electronic devices (CIEDs) have been followed with periodic clinic visits. The number of patients with CIEDs has been increasing and CIEDs have become more complex. The workload of both medical staff and patients for CIED follow-up has also been increasing. Remote monitoring (RM) technology has undergone many developments, and RM has been used since 2008 in Japan. The benefits of RM are evident, but there are also problems with the technology. Different systems and various skills are required for RM management compared to conventional follow-up methods.
Preview · Article · May 2014 · Journal of Arrhythmia
[Show abstract][Hide abstract] ABSTRACT: Multi-detector coronary CT angiography (CCTA) can detect coronary stenosis, but it has a limited ability to evaluate myocardial perfusion. We evaluated the usefulness of first-pass CT-myocardial perfusion imaging (MPI) in combination with CCTA for diagnosing coronary artery disease (CAD).
A total of 145 patients with suspected CAD were enrolled. We used 64-row multi-detector CT (Definition Flash, Siemens). The same coronary CCTA data were used for first-pass CT-MPI without drug loading. Images were reconstructed by examining the signal densities at diastole as colour maps. Diagnostic accuracy was assessed by comparison with invasive coronary angiography.
First-pass CT-MPI in combination with CCTA significantly improved diagnostic performance compared with CCTA alone. With per-vessel analysis, the sensitivity, specificity, positive predictive value and negative predictive value increased from 81% to 85%, 87% to 94%, 63% to 79% and 95% to 96%, respectively. The area under the receiver operating characteristic curve for detecting CAD also increased from 0.84 to 0.89 (p=0.02). First-pass CT-MPI was particularly useful for assessing segments that could not be directly evaluated due to severe calcification and motion artefacts.
First-pass CT-MPI has an additional diagnostic value for detecting coronary stenosis, in particular in patients with severe calcification.
[Show abstract][Hide abstract] ABSTRACT: In several cases with idiopathic ventricular fibrillation (VF), VF was initiated by premature ventricular contractions (PVCs) from the Purkinje system. However, the precise characteristics of the Purkinje activity in patients with idiopathic VF remain unclear. We performed an electrophysiological study in a patient with idiopathic VF and examined the correlation between the Purkinje potential and the incidence of PVCs/polymorphic ventricular tachycardia (PMVT). In this case of idiopathic VF, the Purkinje activity caused multiform PVCs and PMVT. The The Purkinje activity and slow conduction of Purkinje fibers are associated with the occurrence of multiform PVCs and PMVT.
No preview · Article · Apr 2014 · Internal Medicine
[Show abstract][Hide abstract] ABSTRACT: Background: A major cause of heart failure (HF) related hospitalizations is fluid accumulation. Recent studies have suggested that intrathoracic impedance (ITI) may be a useful parameter to track daily changes in pulmonary fluid status. OptiVol alert (OA), which is a fluid status algorithm calculated from ITI, can detect impending fluid accumulation at an early stage. However, the sensitivity and specificity of OA for deteriorated HF have not been sufficient for it to be a clinically useful parameter. Therefore, we sought to examine the difference of various parameters between OA and baseline.
Objectives: The purpose of study 1 was to examine how various parameters changed in OA compared to baseline. And the purpose of study 2 was to evaluate what parameters could predict increased log BNP.
Methods: This study was a prospective multicenter study. Patients who suffered from structural heart disease and who had been implanted with a high energy device with an OptiVol feature were included in this study. The patients underwent various examinations at enrolment and following an OA. In study 1, primary endpoint was to examine how log BNP changed between OA and baseline. Secondary endpoint was to examine how other parameters changed between OA and baseline. We defined low ITI as equal or less than 96% of ITI at baseline.
Results: From 2010 to 2011, 200 patients in 12 institutes were enrolled in the present study. Mean age was 65.3 years, mean ejection fraction was 44.2% and mean log BNP was 2.2 ng/ml. We had 376 OA events and 289 periodical follow-up events. In primary endpoint of study 1, there was no significant difference in log BNP between OA and baseline. However, the change rate of ITI was negatively correlated with the change rate of log BNP (r = -0.35, p < 0.01). In 115 OA events with low ITI, log BNP was significantly higher than that at baseline (2.33 vs 2.19, p < 0.01). In secondary endpoint of study 1, there was no significant difference in body weight, cardio-thoracic ratio in chest X ray, end diastolic volume, end systolic volume and tricuspid regurgitation pressure gradient between OA and baseline. In study 2, we searched what parameters could predict increased log BNP by 0.4 compared to that at baseline. To predict increased log BNP by 0.4, the area under ROC curve for OA events with low ITI was significantly larger than that for only OA events (0.78 vs 0.62, p < 0.01).
Conclusions: There was no significant difference in log BNP between OA and baseline. However, OA events with low ITI can predict increased BNP, but only OA events.
Preview · Article · Oct 2013 · Journal of Cardiac Failure
[Show abstract][Hide abstract] ABSTRACT: Introduction: Implantable cardioverter defibrillator (ICD) has been widely used across the world. However, there have been many problems including inappropriate therapies (IAT). IAT caused psychological damage and poor prognosis. Although each company has original algorithms to avoid IAT due to supraventricular tachycardia (SVT), we sometimes have experienced IAT due to SVT. Because recent algorithm to discriminate SVT from ventricular tachycardia (VT) was very complicated, it is difficult to know how we should manage the algorithm setting after IAT events. Then, we sought to examine which algorithm is superior to avoid IAT due to SVT in a simulation.
Methods: We collected the intracardiac electrogram of IAT due to SVT. And we created the program to reproduce the same SVT by using the information of AA interval, VV interval and AV interval. We employed ViP-II (Medtronic) as a stimulator, which could deliver the electrical pulse to ICD in same timing as the IAT events. We tested Protecta®, Promote™, INCEPTA™, Lumax® and PARADYM DR™ in nominal setting and modified setting. In nominal setting, cutoff rate of VF zone was 180 beat per minute (bpm) and VT zone was 150 to 180 bpm.
Results: Twenty-seven IAT events were examined, 14 IAT events were due to rapid atrial fibrillation (AF) and 13 IAT events were due to paroxysmal SVT (PSVT). In nominal setting (VF zone was above 180bpm and VT zone was from 150 to 180 bpm), mean IAT rate in rapid AF and in PSVT was 78.5±17.5% and 90.8±8.4%, respectively. When we set cutoff rate of VF zone to 240 bpm and VT zone from 150 to 240 bpm, IAT rate due to rapid AF was significantly reduced (78.6±17.5% vs 32.9±21.2%, p < 0.01). However, even though we changed various parameters such as VF zone setting, blanking period, stability or onset criteria, the IAT rate due to PSVT did not significantly reduce.
Conclusions: The simulation seems to be useful to find the appropriate setting to avoid IAT. High VF zone setting seems to be useful to avoid IAT due to rapid AF. However, there was no superior algorithm to avoid IAT due to PSVT. Another method such as morphology criteria or catheter ablation may be necessary to avoid IAT due to PSVT.
Full-text · Article · Aug 2013 · European Heart Journal
[Show abstract][Hide abstract] ABSTRACT: Background: Early initiation of corticosteroid therapy is recommended for patients with cardiac sarcoidosis. Cardiac sarcoidosis is frequently presented as high-degree atrioventricular block in females, indicating that cardiac sarcoidosis can be detected in the early phase of the disease. Females may have a better response than males to corticosteroid therapy.
Purpose: The purpose of this study was to determine the clinical factors of response to corticosteroid therapy and the gender difference in the efficacy of corticosteroid therapy for left ventricular (LV) function in patients with cardiac sarcoidosis.
Methods: A total of 28 patients with cardiac sarcoidosis who were treated with initial corticosteroid at a dose of 30 or 40 mg daily were included. The corticosteroid was tapered over a period of 6 to 12 months to a maintenance dose of 5 to 10 mg daily. We assessed the changes in LV ejection fraction (EF) before and after corticosteroid therapy retrospectively.
Results: The mean age of the patients was 62±11 years. The majority of patients were females (68%). At 1 year after the start of initial corticosteroid therapy, 13 of the 28 patients had improvement in LVEF. Female (OR: 13.6, 95% Cl: 1.19-499, P = 0.035) and inflammatory cell infiltration finding on endomyocardial biopsy (OR: 9.34, 95% Cl: 1.08-208, P = 0.041) were independent predictors of LVEF improvement. Regarding the gender difference in the efficacy of corticosteroid therapy, the degree of improvement in LVEF at 1 year after the start of corticosteroid therapy was greater in females than in males (6±11% vs. -5±7%, P = 0.013). When we evaluated the 20 patients with reduced LVEF at the time of diagnosis (LVEF < 50%), all of the males had decreased LVEF but 10 of 13 females had improved LVEF. The degree of improvement in LVEF was greater in females than in males (8±13% vs. -8±4%, P = 0.004). The degree of improvement in LVEF at 5 years after the start of corticosteroid therapy was also greater in females than males, particularly in patients with reduced LVEF at the time of diagnosis.
Conclusions: Female and inflammatory cell infiltration finding on endomyocardial biopsy were associated with improvement in LV function after initial corticosteroid therapy. The efficacy of corticosteroid therapy for LV function was greater in females than in males. Our findings suggest that there is a gender difference in the efficacy of corticosteroid therapy for cardiac sarcoidosis.
Full-text · Article · Aug 2013 · European Heart Journal
[Show abstract][Hide abstract] ABSTRACT: PurposeThe purpose of this study was to clarify the prognosis of cardiac resynchronization therapy with defibrillators (CRT-Ds) in Japan.Methods
We selected 384 patients implanted with a CRT-D device from the observation database (n=1482) of the Japanese Cardiac Device Therapy Registry. We investigated the CRT criteria, including the presence of New York Heart Association (NYHA) class III/IV symptoms, left ventricular ejection fraction (LVEF) ≤35%, and QRS duration ≥120 ms. The patients were divided into 2 groups: the group fulfilling all of the 3 criteria (Group A, n=229) and the group not fulfilling the criteria (Group B, n=155). We compared mortality and appropriate shock rates between the 2 groups.ResultsThere was no significant difference in mortality (17.9% vs. 13.5%) or appropriate shock rates (32.5% vs. 31.6%) during the observation period of 29.0±15.7 months between the 2 groups. A logistic multivariate analysis showed that appropriate shocks (hazard ratio [HR]=1.85) and class III antiarrhythmic agents (HR=2.33) were independently associated with all-cause death, and that age ≥70 years (HR=0.55), male gender (HR=2.07), and presence of a single-chamber device (HR=1.78) were associated with appropriate shocks. The prognosis of Group A was better than that of the COMPANION trial.Conclusions
Japanese patients with CRT-D devices had a better prognosis than did those in the COMPANION trial, but no significant differences were observed between patients fulfilling and those not fulfilling the above mentioned criteria.
Preview · Article · Jun 2013 · Journal of Arrhythmia
[Show abstract][Hide abstract] ABSTRACT: Background:
We investigated the acute effects of implantable cardioverter-defibrillator shock on myocardium, cardiac function, and hemodynamics in relation to left ventricular systolic function.
Methods and results:
We studied 50 patients who underwent implantable cardioverter-defibrillator implantation and defibrillation threshold (DFT) testing: 25 patients with left ventricular ejection fraction (LVEF) ≥ 45% and 25 patients with LVEF <45%. We measured cardiac biomarkers (creatine kinase, creatine kinase-MB, myoglobin, cardiac troponin T and I, and N-terminal probrain natriuretic peptide). Left ventricular relaxation was assessed by global longitudinal strain rate during the isovolumetric relaxation period using speckle-tracking echocardiography. Blood sampling and echocardiography were performed before, immediately after, and 5 minutes and 4 hours after DFT testing. Mean arterial pressure was measured directly during DFT testing. Cardiac biomarkers showed no significant changes in either group. LVEF was decreased until 5 minutes after DFT testing and had recovered to the baseline at 4 hours in the group with reduced LVEF (P<0.001), whereas LVEF reduction was not observed in the group with preserved LVEF (P=0.637). Global isovolumetric relaxation period was decreased until 5 minutes after DFT testing and had recovered to the baseline at 4 hours in both groups (preserved LVEF: 0.39 ± 0.14 versus 0.23 ± 0.13* versus 0.23 ± 0.13* versus 0.40 ± 0.13 s(-1), *P<0.001 versus baseline; reduced LVEF: 0.15 ± 0.05 versus 0.08 ± 0.04† versus 0.09 ± 0.04† versus 0.15 ± 0.05 s(-1), †P<0.001 versus baseline, repeated-measures ANOVA). Time to recovery of mean arterial pressure to the baseline was prolonged in the group with reduced LVEF (P<0.001).
Implantable cardioverter-defibrillator shock transiently impairs cardiac function and hemodynamics especially in patients with systolic dysfunction, although significant tissue injury is not observed.
[Show abstract][Hide abstract] ABSTRACT: Oxidative stress has been implicated in the pathogenesis of heart failure. Reactive oxygen species (ROS) are produced in the failing myocardium, and ROS cause hypertrophy, apoptosis/cell death and intracellular Ca2+ overload in cardiac myocytes. ROS also cause damage to lipid cell membranes in the process of lipid peroxidation. In this process, several aldehydes, including 4-hydroxy-2-nonenal (HNE), are generated and the amount of HNE is increased in the human failing myocardium. HNE exacerbates the formation of ROS, especially H2O2 and ·OH, in cardiomyocytes and subsequently ROS cause intracellular Ca2+ overload. Treatment with beta-blockers such as metoprolol, carvedilol and bisoprolol reduces the levels of oxidative stress, together with amelioration of heart failure. This reduction could be caused by several possible mechanisms. First, the beta-blocking effect is important, because catecholamines such as isoproterenol and norepinephrine induce oxidative stress in the myocardium. Second, anti-ischemic effects and negative chronotropic effects are also important. Furthermore, direct antioxidative effects of carvedilol contribute to the reduction of oxidative stress. Carvedilol inhibited HNE-induced intracellular Ca2+ overload. Beta-blocker therapy is a useful antioxidative therapy in patients with heart failure.
[Show abstract][Hide abstract] ABSTRACT: Syncope in patients with Brugada syndrome is usually associated with ventricular tachyarrhythmia, but some episodes of syncope can be related to autonomic disorders.
The purpose of this study was to investigate the characteristics of syncope to differentiate high-risk syncope episodes from low-risk events in patients with Brugada syndrome.
We studied 84 patients with type 1 electrocardiogram and syncope. Patients were divided into 2 groups: patients with prodrome (prodromal group; n = 41) and patients without prodrome (nonprodromal group; n = 43).
Ventricular fibrillation (VF) was documented at index event in 19 patients: 4 patients (21%) with documented VF experienced a prodrome prior to the onset of VF, whereas 15 patients (79%) did not have symptoms prior to documented VF (P <.01). Twenty-seven patients in the prodromal group and 7 patients in the nonprodromal group were considered to have syncope related to autonomic dysfunction. Syncope in other patients was defined as unexplained syncope. During the follow-up period (48 ± 48 months), recurrent syncope due to VF occurred in 13 patients among patients with only unexplained syncope and was more frequent in the nonprodromal group (n = 10) than in the prodromal group (n = 3; P = .044). In multivariate analysis, blurred vision (hazard ratio [HR] 0.20) and abnormal respiration (HR 2.18) and fragmented QRS (HR 2.39) were independently associated with the occurrence of VF.
Syncope with prodrome, especially blurred vision, suggests a benign etiology of syncope in patients with Brugada syndrome.
Full-text · Article · Nov 2011 · Heart rhythm: the official journal of the Heart Rhythm Society
[Show abstract][Hide abstract] ABSTRACT: Intermittent arm ischemia before percutaneous coronary intervention induces remote ischemic preconditioning (RIPC) and attenuates myocardial injury in patients with myocardial infarction. Several studies have shown that intermittent arm ischemia increases coronary flow and is related to autonomic nerve system. The aim of this study was to determine whether intermittent arm ischemia induces vasodilatation of other arteries and to assess changes in the autonomic nerve system during intermittent arm ischemia in humans. We measured change in the right brachial artery diameter during intermittent left arm ischemia through three cycles of 5-min inflation (200 mmHg) and 5-min deflation of a blood-pressure cuff using a 10-MHz linear array transducer probe in 20 healthy volunteers. We simultaneously performed power spectral analysis of heart rate. Ischemia-reperfusion of the left arm significantly dilated the right brachial artery time-dependently, resulting in a 3.2 ± 0.4% increase after the 3rd cycle. In the power spectral analysis of heart rate, the high-frequency domain (HF), which is a marker of parasympathetic activity, was significantly higher after the 3rd cycle of ischemia-reperfusion than baseline HF (P = 0.02). Intermittent arm ischemia was accompanied by vasodilatation of another artery and enhancement of parasympathetic activity. Those effects may play an important role in the mechanism of RIPC.
No preview · Article · Sep 2011 · The Journal of Physiological Sciences